The present invention relates to improvements to a mixer which is particularly usable for fibrous products in the zootechnical field but can also be used in the industrial field.
Mixers are currently known which are substantially constituted by a supporting base which is fixed or downwardly provided with wheels which allow its transport, above which a container is bolted or welded and is internally provided with one or more vertical mixing screws, each whereof is welded to an axial shaft which is rotationally associated with end pivots and is rotated by appropriate mechanical transmissions connected to actuation elements.
In particular, each screw has a spiral-shaped profile which is arranged along an ideal conical surface and therefore tapers from the bottom toward the top and ends at a position which is spaced from the top of said shaft.
The screw may conveniently be provided on its profile with blades adapted to shred the fibrous products during rotation.
During the operation of said mixers, the screw forces the loaded to rise toward the apex of the screw itself; when the product reaches said top, it falls downward to resume its rising motion, since the transport means which forced it to rise are no longer acting.
Though they optimally achieve their purposes, said known mixers, in particular for fibrous products such as hay and straw, have a disadvantage which consists in the easy tangling of said products around the portion of shaft which is arranged above the top of the screw.
Said tangling occurs in particular if the mixed products are moist.
Such a disadvantage entails the need to periodically stop the mixing and clean the shaft.